Oct 4, 2026·Special Population & Related Conditions
OCD and IQ: Is Obsessive-Compulsive Disorder Linked to High Intelligence?
OCD IQ scores fall in the normal range: a meta-analysis of 98 studies found people with OCD score slightly below controls, with speed-based scores lowest.
Dr. Russell T. WarneChief Scientist
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OCD IQ research does not support the idea that obsessive-compulsive disorder goes with high intelligence: a meta-analysis of 98 studies found that people with OCD score slightly below comparison groups on average, while still within the normal range. The largest gap is on the timed, nonverbal side of IQ tests, which fits a well-documented slowing in processing speed.
This article looks at where the high-IQ idea comes from, what the IQ data show, the profile of thinking skills under the overall score, why timed subtests matter for this group, how OCD relates to school outcomes and change over time, and what a single score can tell you. OCD affects a minority of people: in a nationally representative U.S. survey, Ruscio and colleagues found a lifetime prevalence of 2.3%, even though more than a quarter of respondents reported obsessions or compulsions at some point. The same survey found that OCD often occurs alongside anxiety disorders and mood disorders.
Where the "OCD means high IQ" idea comes from
The belief is old. Abramovitch and colleagues note that "it has long been speculated that the disorder is associated with elevated intellectual capacity," even though little research had focused on IQ in OCD before their review.
Part of the appeal is probably that OCD involves a lot of thinking: intrusive doubts and long chains of reasoning about risk. A person can describe those thoughts in vivid, articulate detail. Articulate description reflects verbal skill and insight, which is a narrower thing than general intelligence measured on a standardized test, and the only way to settle the question is to compare test scores.
What the IQ data show
The most complete answer comes from the 2018 meta-analysis by Abramovitch, Anholt, Raveh-Gottfried, Hamo and Abramowitz. They found 98 studies that reported IQ for people with OCD and for comparison groups without a psychiatric diagnosis, and computed 108 effect sizes: 40 for full-scale IQ, 55 for verbal IQ and 13 for performance IQ.
• Full-scale and verbal IQ: People with OCD scored lower than controls, with small effect sizes. Their mean scores were still in the normative range.
• Performance IQ: The gap was larger, a moderate effect size, on the nonverbal subtests that make up performance IQ.
No clinical or demographic factor the authors examined significantly changed these results. Their conclusion was that OCD "is associated with normative FSIQ and VIQ, and relatively lowered PIQ." In plain terms, the typical person with OCD has an ordinary IQ, a little below that of comparable people without the disorder.
Population data point the same way. In the Dunedin cohort in New Zealand, Koenen and colleagues tested 1,037 children on the WISC-R and followed them to age 32. Seventeen had past-year OCD at 32, spread across the IQ range with no clear high-IQ pattern (2.6% of those with childhood IQ of 85 or below and 2.8% of those at 115 or above). Seventeen cases is too few for firm conclusions, but there was no sign of the high-IQ concentration the stereotype predicts.
One newer study adds nuance. Among 341 adolescents seeking psychiatric help in Italy, Stefanelli and colleagues found an inverted U: teenagers with mild obsessive-compulsive symptoms had somewhat higher IQ than those with none or with severe symptoms. The sample was young people with a range of psychiatric problems, and symptoms were rated on a scale, so the study does not show that OCD itself raises IQ.
The cognitive profile under the full-scale score
A full-scale IQ is a summary. Neuropsychological studies of OCD look at specific skills, and the profile they find is uneven. Abramovitch, Abramowitz and Mittelman meta-analyzed 115 studies of 3,452 adults with OCD across 10 domains:
• Medium effects: All subdomains of executive function, processing speed and sustained attention.
• Small effects: Visuospatial abilities, working memory and verbal memory.
• A large effect: Nonverbal memory, the one domain linked in their analysis to weaker executive function.
A separate meta-analysis of 88 studies by Shin and colleagues found deficits in visuospatial memory, executive function, verbal memory and verbal fluency, with the largest effect in recalling complex visual designs. Auditory attention was preserved. The authors described the deficits as wide-ranging but "not so large in general."
"Executive functions" are the planning, switching and self-monitoring skills that organize other thinking, and they are measured with tasks described in our article on executive function tests. Because the nonverbal memory gap tracked weaker executive function in the adult meta-analysis, part of it may reflect difficulty organizing complex material while learning it, which is an executive skill.
Why timed subtests can pull scores down
Most of the nonverbal subtests that formed performance IQ on older Wechsler scales are timed, and several award bonus points for speed. A person who works slowly and carefully can understand a task perfectly and still lose points. Abramovitch's team linked the lower performance IQ in OCD to "the putative impact of reduced processing speed in this population," and the adult meta-analysis found medium-sized deficits in processing speed.
This matters when reading an individual report. On modern tests, speed is concentrated in a separate index, explained in our guide to the processing speed index. A low processing speed index alongside average or higher reasoning and verbal scores is a common shape for many conditions, and it can lower a full-scale IQ without reflecting weaker reasoning. Examiners note behavior during testing, such as rechecking answers, so the score can be interpreted in context.
Children, school and change over time
Children with OCD look somewhat different from adults. A meta-analysis of pediatric studies by Abramovitch and colleagues found small effect sizes across all nine neuropsychological domains, none statistically significant, and concluded that youth with OCD "do not exhibit noteworthy neuropsychological deficits." Only 11 controlled studies were available, so this is a thin evidence base.
School outcomes are a different story. In a Swedish register study of 2,115,554 people, Pérez-Vigil and colleagues found that the 15,120 diagnosed with OCD were less likely to finish upper secondary school (adjusted odds ratio 0.43) or to finish a university degree (0.59). The results held when siblings were compared and were stronger when OCD began before age 18. Excluding people with other psychiatric diagnoses weakened the estimates without removing them. Because ability tests in the meta-analyses show only small gaps, the school findings may reflect the burden of symptoms and other conditions at least as much as ability.
Are the test differences a lasting trait or a product of current symptoms? In a randomized trial of group cognitive behavioral therapy, Braga and colleagues found that OCD symptoms improved over 12 weeks while neuropsychological test scores did not change, and test performance did not predict who responded. That fits the view that the modest cognitive differences are fairly stable, although longer studies are needed.
What an IQ score can and cannot show
For a person with OCD, a full-scale IQ is likely to land in the ordinary range and can understate reasoning ability if timed subtests drag it down. Looking at index scores, and at how the person approached the tasks, gives a truer picture than the single number.
When cognitive concerns are part of the clinical picture, assessment is usually done by a clinical psychologist or neuropsychologist using a broader battery, as described in our overview of neuropsychological testing. Questions about diagnosis, symptoms or treatment belong with a psychiatrist, psychologist or the person's care team.
Frequently asked questions
Do people with OCD have a higher IQ?
No. A meta-analysis of 98 studies found that people with OCD score slightly lower than comparison groups on average, with mean scores in the normal range.
Why might someone with OCD score lower on an IQ test?
The biggest gap is on timed nonverbal subtests, and adults with OCD show medium-sized deficits in processing speed. Slow, careful work can cost points on timed items even when the reasoning is sound.
Is OCD linked to executive function problems?
On average, yes, with medium-sized differences in adult studies of planning, flexibility and inhibition. Individual results vary widely, and studies of children have found only small differences.
Does OCD affect school performance?
In a Swedish study of over two million people, those with OCD were less likely to finish upper secondary school or university, especially when OCD began in childhood.
Can an IQ test diagnose OCD?
No. OCD is diagnosed clinically by a psychiatrist, psychologist or other qualified clinician, and IQ scores cannot identify the disorder.
The takeaway
OCD IQ research turns the stereotype around. Across 98 studies, people with OCD scored slightly below comparison groups, with averages in the normal range and the largest gap on timed nonverbal tasks. Under the full-scale score, adults show modest differences in executive function and speed and a larger one in nonverbal memory, while children show smaller differences. A careful reading of index scores and test behavior tells you more than the overall number. If you want to see how a standardized score is built and reported, you can try an online IQ test built by psychometricians that reports results against a defined norm group.
References
1. Ruscio, A. M., Stein, D. J., Chiu, W. T., & Kessler, R. C. (2010). The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication. Molecular Psychiatry, 15(1), 53-63. doi.org
2. Abramovitch, A., Anholt, G., Raveh-Gottfried, S., Hamo, N., & Abramowitz, J. S. (2018). Meta-analysis of intelligence quotient (IQ) in obsessive-compulsive disorder. Neuropsychology Review, 28(1), 111-120. doi.org
3. Koenen, K. C., Moffitt, T. E., Roberts, A. L., Martin, L. T., Kubzansky, L., Harrington, H., Poulton, R., & Caspi, A. (2009). Childhood IQ and adult mental disorders: A test of the cognitive reserve hypothesis. American Journal of Psychiatry, 166(1), 50-57. doi.org
4. Stefanelli, R., Orlandi, M., Bouter, D. C., Fusar-Poli, P., Tonna, M., Borgatti, R., & Mensi, M. M. (2025). IQ and socio-occupational functioning in relation to obsessive-compulsive symptoms severity in a clinical sample of adolescents. Scientific Reports, 15, 14021. doi.org
5. Abramovitch, A., Abramowitz, J. S., & Mittelman, A. (2013). The neuropsychology of adult obsessive-compulsive disorder: A meta-analysis. Clinical Psychology Review, 33(8), 1163-1171. doi.org
6. Shin, N. Y., Lee, T. Y., Kim, E., & Kwon, J. S. (2014). Cognitive functioning in obsessive-compulsive disorder: A meta-analysis. Psychological Medicine, 44(6), 1121-1130. doi.org
7. Abramovitch, A., Abramowitz, J. S., Mittelman, A., Stark, A., Ramsey, K., & Geller, D. A. (2015). Research review: Neuropsychological test performance in pediatric obsessive-compulsive disorder, a meta-analysis. Journal of Child Psychology and Psychiatry, 56(8), 837-847. doi.org
8. Pérez-Vigil, A., Fernández de la Cruz, L., Brander, G., Isomura, K., Jangmo, A., Feldman, I., Hesselmark, E., Serlachius, E., Lázaro, L., Rück, C., Kuja-Halkola, R., D'Onofrio, B. M., Larsson, H., & Mataix-Cols, D. (2018). Association of obsessive-compulsive disorder with objective indicators of educational attainment: A nationwide register-based sibling control study. JAMA Psychiatry, 75(1), 47-55. doi.org
9. Braga, D. T., Abramovitch, A., Fontenelle, L. F., Ferrão, Y. A., Gomes, J. B., Vivan, A. S., Ecker, K. K., Bortoncello, C. F., Mittelman, A., Miguel, E. C., Trentini, C. M., & Cordioli, A. V. (2016). Neuropsychological predictors of treatment response to cognitive behavioral group therapy in obsessive-compulsive disorder. Depression and Anxiety, 33(9), 848-861. doi.org
Hero image: Washing hands with soap (1), by Beat Ruest, licensed CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0). Via Wikimedia Commons.
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